Plastic containers obtained by forming a polyethylene terephthalate and the like have been widely put into the practical use as containers for containing beverages. A preform which is a precursor to the plastic container is, usually, formed in an injection-forming machine. In recent years, however, forming has been attempted by using a compression-forming system, and various improvements have been made. In carrying out the compression-forming, the molten resin extruded from the extrusion port of a die head is fed (conveyed) to the compression-forming system in a manner as described below.
The synthetic resin heated and melted in the extruder is extruded from the extrusion port of the die head provided in the extruder and is, thereafter, cut by a cutter of a molten resin mass-feeding (conveying) device that is rotating, and is cut from the extrusion port. The molten resin mass after cut is fed into a holder of a holder unit provided in the molten resin mass-feeding device. The holder unit so moves as to follow up part of the rotary track of the metal mold provided in the compression-forming system. The holder of the holder unit moves the molten mass that is fed to a position over the metal mold, permits it to fall into a forming hole of the metal mold (usually, a female mold) in a section in which it is following up the rotary track so that the molten resin mass is handed over thereto.
The following patent document 1 discloses a compression-forming system inclusive of an extruder, a molten resin cutting/conveying device (molten resin mass-feeding device) and a compression-forming machine.
The following patent document 2 discloses a compression-forming system in which a molten resin mass fed into the female mold of the metal mold is compression-formed by the female mold in cooperation with a male mold provided in the compression-forming system so as to be formed into a preform of a predetermined shape.